/*
 * Copyright (C) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.sentry;

import io.sentry.util.Objects;

import java.util.Random;

import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.TestOnly;

/**
 * TracesSampler
 *
 * @since 2021-06-02
 **/
final class TracesSampler {
    private final @NotNull SentryOptions options;
    private final @NotNull Random random;

    TracesSampler(final @NotNull SentryOptions options) {
        this(Objects.requireNonNull(options, "options are required"), new Random());
    }

    @TestOnly
    TracesSampler(final @NotNull SentryOptions options, final @NotNull Random random) {
        this.options = options;
        this.random = random;
    }

    boolean sample(final @NotNull SamplingContext samplingContext) {
        if (samplingContext.getTransactionContext().getSampled() != null) {
            return samplingContext.getTransactionContext().getSampled();
        }
        if (options.getTracesSampler() != null) {
            final Double samplerResult = options.getTracesSampler().sample(samplingContext);
            if (samplerResult != null) {
                return sample(samplerResult);
            }
        }
        if (samplingContext.getTransactionContext().getParentSampled() != null) {
            return samplingContext.getTransactionContext().getParentSampled();
        }
        if (options.getTracesSampleRate() != null) {
            return sample(options.getTracesSampleRate());
        }
        return false;
    }

    private boolean sample(final @NotNull Double doubleValue) {
        return !(doubleValue < random.nextDouble());
    }
}
